1. Field of the Invention
The present invention relates to an optical sensing system, and more particularly, to an optical sensing system for detecting displacements of a slidable frame along an elongated plate.
2. Description of the Prior Art
Linear variable resistors are widely used as input devices in electronic systems. A slidable button is usually provided to engage with a fixed resistor so as to change its resistance. The contacting portions of such a variable resistor may easily get damaged after frequent use which will cause inaccuracy in measuring the resistance of the variable resistor.